The agreed contests come weeks after both candidates ironed out details about when and what the debates would be about. Last month, O'Rourke rejected a proposal by Cruz claiming his campaign had made an ultimatum about the time, place, moderators and issues.

One of the issues O'Rourke raised against the initially proposed debates was that they all took place on a Friday. The newest wave of agreed upon debates occur on a Friday, Sunday and Tuesday.

The race between Cruz and O'Rourke has tightened to single digits in recent weeks. The latest polls averaged by RealClearPolitics shows Cruz leading O'Rourke by 3.2 percentage points.